Process for the manufacture of zinc



u y H. E. COLEYY 1,721,373

PROCESS FOR THE MANUFACTURE OF ZiNC Filed Aug. 8, 192'? V HenrJE. CaZej supply of hydrocarbon.

The essential feature of the process so Patented July 16, 1929. I

UNlT I HENRY EDWIN COLEY, OF LONDON, ENGLAND.

PROCESS FOR Tl-IE MANUFACTURE OF ZINC.

' Application filed August 8, 1927, Serial No. 211,293; and in. Great Britain February 2, 1927.

This invention relates to a process of manufacturing Zinc wherein a hydrocarbon or h \'drocarbon containing body is employed the. hydrocarbon being decomposed to form a reducing agent to effect the reduction 'of the ore, oxide or the like. In this respect the process according" to the present invention is similar to other processcs in which a solid, liquid, or gaseous hydrocarbonis used as an aid to reduction. in all known processes of this character car- 'bon in the ordinary or molecular state is formed and effects the reduction, by the present process carbon in statu masceudi or in the atomic state is produced and in this state is caused to react on the ore to be reduced. This has the effect of reducing the ore more rapidly and more completely than is possiblc'by carbon in the ordinary or molecular state. 1

. I have found that to produce and use the carbon in its nascent or atomic state the heat necessary for effecting its decomposition must be imparted to it by, and as a result of,

' actual'contact withthc oreto be reduced and such ore. as a consequence, must first of all have been hrought'upto a temperature which is sutlicient to enable the reduction to take place and to both effect thedecomposition of the hydrocarboir'at the moment of its first cont-act and to'continue to effect the decomposition of the continuing cordingto the present invention being the utilization of carbon in its nascent or atomic I state for effecting the reduction it follows that thecarbon in this state can be obtained from a hydrocarbon which is initiallyin a solid, liquid, or gaseous form or from a body containing or forming a hydrocarbon the only essential being that such hydrocarbon is not allowed to decompose before -it has actually comeinto contact with ore previously heated to a reducing temperature.

. For'a proper understandingto be Ob-f tained of the different sets of conditi,ons'

' v whichfoccur in producing b o n carbon in the. ordinary or molecular state and on the other hand carbon inthe nascent or atomic state it must be realizedthat unfless the hydrocarbonisallowed to attain I But whereas critical or decomposition temperature onlyat the moment of its contact with the ore to be reduced and by reason of thiscontact carbon in its ordinary or molecular state is always formed. On the other hand by allowing the hydrocarbon to be brought to its critical or decomposition temperature only at the moment of its contact with the ore will be released. This occurs repeatedly without exception as decomposition of-the hydrocarbon always takes place before the v ore has attained its reducing temperature. 2

If the ore is heated up to the reduc inc; temperature first and a hydrocarbon is projected into the heated reducing chamber above the ore decomposition of the hydrocarbon takes place before the hydrocarbon can possibly reach the ore and carbon in the ordinary or molecular state is released. '80

This, is proved by the fact that soot is deposited over the surface of the ore. v

If alarge quantity of a cold hydrocarbon gas is rapidly blown through the heated ore within the'iglucing' chamber the $5 ore is thereby cooled to below its reducing temperature and practically no reduction will take place. By thismethod it hasbjeen found impossible to maintain the ore or-the required reducing temperature which for zinc is at or almost 930 centigrade. As a consequence the decomposition of the hydrocarbon takes place when the ore is at a temperature below that necessary for its re duction.

(4) If the hydrocarbon is admitted together-with air, a flame is produced and as .a result the hydrocarbon is obviously there- {by decomposed before; it can possibly come into contact with the. ore. Any reduction i "which may take place with this method is effected by means of the released hydrocaribon and the GO formed and not bon per se.

by the car 4 As a result of these and other experiments it has been found to be absolutely essential for the ore to be first heated to its reducing temperature and for such heated ore itself to bring the hydrocarbon to its critical ordecomposition temperature for carbon to be released in its nascent or atomic state. In this latter state the carbon is in its most active condition and will effect. the reduction of the ore-far inorerapidly and coinpletely'than is possible when the carbonis in its ordinary or molecular state.

In practice the prematuredecomposition of the hydrocarbon is prevented by artificial-1y cooling the pipe or other means used for conveying the hydrocarbon to the ore suclil asby* surrounding the same with .a cket through which water is continuously circulated.

' in its non-decomposed condition'reaches the and the like may .sentedby the formula C paratus "paratus "The process of manufacturing zinc according to the present invention consists broadly iii-heating the ore to be reduced to'a suitable reducing temperature temperature conveying a hydrocarbon .to'ithe-ere by means of an artificially cooled andwhen the ore is at conyeyjing means so that the hydrocarbon ore and as a result of actual contact with the ore is decomposed and produces carbon in a nascent state.

A hydrocarbon such as crude oil, petroleum or the like or a suitable body containing hydrocarbon such as coal, peat, lignite be used to effect a reduction by the process forming the present invention.

The relative, quantities of ores or the like to hydrocarbon used depend upon two factors viz the zinc content of the material and the nature of the hydrocarbon used an may be best described by the following equation 1- 6ZnO-I- C ,I I =6CO.+6Zn+7H In this equation the h drocarbon repre- 14 is given as being typical only.

Inthe application of my invention it is necessary to carry out the reaction in an apparatus of suitable construction, so designed that while the process is being carried out air may be excluded if desired'from the apand preferably designed that the material to be treated may be passedcontinuously through the apparatus. The apmay be made of any suitable material but this inaterial depends upon the nature of the ore or oxide to be treated and upon the temperature at which the reaction must take place. The apparatus may consist of a chamber or cylinder which can be rotated in order to provide agitation tothe ores, etcetera to be treated, or which may be fixed and provided with internal a itating means such as rotary bafiies, so that the angles to The reduced metal The apparatus illustrated in thedrawings comprises a rotatable tube 1 constituting the- Tliis tube which is adapted to be heated preferably externally'and en reducing chamber.

tirely or partly by the burning of the gas produced by the reaction is supported upon rollers which engage circumferential flanges 3 on the exterior of the tube. These rollers are preferably of a comparatively large diameter and either the rollers or the flanges may be of increasing width towards one end of the tube to allow tube.

free ingress of air is so constructed and ar ranged as to allow for the introduction of the orcs or the like at one end and the extraction of the gangue at the other end. passes out with and at the same end of the tube'as the gases.

The hydrocarbon or hydrocarbon containing body when in the liquid form may be led into the interior of the tube at either end by for carrying into effor the expansion of the The tube although sealed to prevent-the way of awater cooled pipe 4 which as 111- d dicated by the dotted lines extends down the interior of the tube a distance suitable for the effective working of the process. If the hydrocarbon or hydrocarbon containing body is not in the liquid form 'it may be led into the interior of the tube by means of a water cooled or other artificially cooled conveyor.

By -this means the hydrocarbon is caused to maintain its original or nondecomposed condition until the same actually comes into contact with the heated ore or the 4 like within the tube 1 when the hydrocarbon undergoes decomposition, yielding products of a highly active reducing nature such as nascent carbon, nascent hydrogen etcetera. .This pipe-4 is surrounded by an outer jacket 5 through which in the present example a stream of water is caused to circulate.

The inlet for such cooling water is indithe hydrocarbon is caused to maintain its original condition until the same actually comes. into contact with the heated ore or the like within the. tube 1 when it disintecated at 6 and its outlet at 7 By this means v the same through grates and forms-nascent carbon Wliicll' duced into the tube 1 is preheated to preferably a reducing temperature. This is etl fected in the example illustrated bypassing a rotating tube 8. see Fig.

. 2, whichis disposed at right angles to the,

main tube 1. Thepreheated tube 8 is fed from a hopper 9 by means of a suitable conveyor 10 and it dischargesthe preheated ore into the *feed hopper 11 of the main tube 1.

From this hopper 11. the ore is conveyed, by means of the conveyor. 12, through the wall of and into' the interior of a casing forming. one part of the gas take-off or vapour outlet 13. From the interior of this casing the oreis picked up by means of a scoop 14, mounted .upon one end of and revolving with the main tube 1. which is set at a. slight declination so that the ore works its Way slowly through the tube to the op* positeend.

As before described the hydrocarbon containing body may be" introduced at the opposite end of the tube to that into which the fresh ore is in'tro luced. As a consequence of this fact and thefact that the ore' is preheated to at .or about'a reducing temperature 'before'it is passed into-the'reducing' tube a reducingprocess goes on throughout practically the entire length of the reducing'tube. By thismeans. the complete reduction desired is facilitatedin that the reducing'agent when in a condition of least activity comes into contact with the fresh and therefore richest ore at {the inlet end of the tube whilst the poorest-"ore which is not affected by the redti'cing agent in this condition is subjecte'chto' the hydro carbon at or adjacent to the point-of its introduction into the reducing tube} .7

The reduced metal in the form of a vapour passes out of. the tube 1" with the gases through thevapourbutletj-f13 whilst" the gangue is discharged'into the receptacle 15 from the bottom-of which it is continu ously removed by means of the conveyor 16. It will thus be seen that by meansof an apparatus as above described the process is a continuous one, the cold ore being fed into the hopper 9 and the gangue discharg g ed automatically and continuously by the con: veyor 16. Air is excluded from the tube during the; process to prevent re-oxidation of the metal and this is efi'ected'by the provision of gas tight joints at both ends of'the tube.

Owing to the temperature at which the joint at the gas take-off end of-the tube is required to work, .existing types of joint are unsuitable. 1 U

The joint at-this end a cording to the 1 to the inner end of the able surface 24 example illustrated .comprises. a stationary v outer casing 17 forming partof or attached gas take-otl' 13.

The correspondingend of casting forming the i I Th s casing consists oi. an. annular plate 18, and a circumferential When the apparatus is assembled the gas take-off end of the tube 1 projects through the aperture in the plate 18 and the flange 20 on this end of the tube resides within the shrouding formed by the'horizontal flange 19. The required gas tight joint is formed by interposing a suitable packing 21 between the opposing faces tube and theolate 18 and applying spring or other pressure to the tube 1 so as to hold the flange 20 hard against the packing and: to compensate for expansionof the tube 1.

From experiments so far madeI have found'th-at the most suitable packing is a machined block of wrought iron. Such a packing-material besides providing a gas tight joint will stand up to thc .high temperature to which it is normally subjected.

of the flange 20 on the.

Any other suitable metal or alloy of metals may however be usedin lieu of the wrought iron. j

F ronriny experiments in this direct-ion I have found that iron or steel Wire, preferably. iii rope form, packing material which besides providing a tight joint stands up to the high temperaturesto which it is normally subjected.

The above mentioned pressure applied in the example illustrated through the me,- dium of a bell crank lever 22, a spring'23 or constitutes a suitable springs acting upon'one arm of-such lever,

the other armapplying pressure. to a suit on the tube through a roller 23 or other anti-friction device.

' The gangue discharge end of the tube may be supported in any suitable manner so ascto bearing having a stufling' box 26 and a gland packing 27. j

. Claims:

l. method of reducing zinc-bearing material which consists in The pressure thusv acts in a direction axial of the tube.

exclude-air but preferably. by means of a temperature, agitating the samein an air excluding vessel 'and Whenat that tempera hydrocarbon cooled below ture introducing a said temperature at a point 11 5 by said mass.

3. A method terial which consists in heating a mass 0 of reducing zinc-bearing maf material heated to its reduction In testimony ormally covered said material to substantially its reduetion temperature within a vesse 1, conducting a sel and up heated mass of the cooled hydrocarbon with the mass 0 I hydrocarbon within the said vessel, cooling 10 the hydrocarbon temperature during its passage below its decomposition into the vesto the moment of cb'ntaet'with the material, and then'contactin i 15 temperature.

whereof I afiix my signature. HENRY EDWIN COLEY. 

